1. Field of the Invention
The present invention relates to organic light emitting displays and manufacturing processes generally and, more particularly, to an organic light emitting display and process in which a pixel defining layer formed on a planarization layer in a region where no first electrode has been formed, is formed with a height that is either lower than, or equal to, that of a pixel defining layer formed on the first electrode.
2. Description of the Related Art
In general, an organic light emitting display manufactured as a flat panel display device is composed of an anode, a cathode, and organic thin layers interposed between the anode and the cathode. The organic thin layers include at least an emission layer, and may further include a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, and so forth, exclusive of the emission layer. This organic light emitting display is divided into two types according to the material constituting the organic thin layers, particularly the emission layer: a first type organic light emitting display which uses a polymer organic light emitting display, and a second type of organic light emitting display that uses a small molecule organic light emitting display.
In order to realize full color in the organic light emitting display, the emission layer should be patterned. There are two methods for patterning the emission layer: one method uses a shadow mask when patterning a small molecule organic light emitting display, and the other method uses either an inkjet printing technique or a laser induced thermal imaging (LITI) technique when patterning a polymer organic light emitting display. Among these techniques, the LITI method has the advantages of being capable of precisely patterning the organic layer and being suitable for patterning a large-sized display with a high degree of resolution, and has the advantage of being a dry process, while the inkjet printing technique is a wet process.
The technique of pattering the organic thin layer by the LITI technique requires at least a light source, a substrate for the organic light emitting display, and a donor substrate. Patterning the organic layer on the substrate is performed in such a manner that light emitted from the light source is absorbed into a light-to-heat conversion layer of the donor substrate to be converted into thermal energy, and then a material forming a transfer layer is transferred to the substrate by the thermal energy. This technique is disclosed in Korean Patent Application Publication No. 1998-51844 and in U.S. Pat. No. 5,998,085 to Isberg et al., entitled PROCESS FOR PREPARING HIGH RESOLUTION EMISSIVE ARRAYS AND CORRESPONDING ARTICLES, issued on Dec. 7, 1999; U.S. Pat. No. 6,214,520 to Wolk et al., entitled THERMAL TRANSFER ELEMENT FOR FORMING MULTILAYER DEVICES, issued on Apr. 10, 2001; and U.S. Pat. No. 6,114,088 to Wolk et al., entitled THERMAL TRANSFER ELEMENT FOR FORMING MULTILAYER DEVICES, issued on Sep. 5, 2000.